package org.bouncycastle.asn1;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

/**
 * DER UniversalString object.
 */
public class DERUniversalString extends ASN1Object implements DERString {
    private static final char[] table = { '0', '1', '2', '3', '4', '5', '6',
            '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
    private byte[] string;

    /**
     * return a Universal String from the passed in object.
     * 
     * @exception IllegalArgumentException
     *                if the object cannot be converted.
     */
    public static DERUniversalString getInstance(Object obj) {
        if (obj == null || obj instanceof DERUniversalString) {
            return (DERUniversalString) obj;
        }

        throw new IllegalArgumentException("illegal object in getInstance: "
                + obj.getClass().getName());
    }

    /**
     * return a Universal String from a tagged object.
     * 
     * @param obj
     *            the tagged object holding the object we want
     * @param explicit
     *            true if the object is meant to be explicitly tagged false
     *            otherwise.
     * @exception IllegalArgumentException
     *                if the tagged object cannot be converted.
     */
    public static DERUniversalString getInstance(ASN1TaggedObject obj,
            boolean explicit) {
        DERObject o = obj.getObject();

        if (explicit || o instanceof DERUniversalString) {
            return getInstance(o);
        } else {
            return new DERUniversalString(((ASN1OctetString) o).getOctets());
        }
    }

    /**
     * basic constructor - byte encoded string.
     */
    public DERUniversalString(byte[] string) {
        this.string = string;
    }

    public String getString() {
        StringBuffer buf = new StringBuffer("#");
        ByteArrayOutputStream bOut = new ByteArrayOutputStream();
        ASN1OutputStream aOut = new ASN1OutputStream(bOut);

        try {
            aOut.writeObject(this);
        } catch (IOException e) {
            throw new RuntimeException("internal error encoding BitString");
        }

        byte[] string = bOut.toByteArray();

        for (int i = 0; i != string.length; i++) {
            buf.append(table[(string[i] >>> 4) & 0xf]);
            buf.append(table[string[i] & 0xf]);
        }

        return buf.toString();
    }

    public String toString() {
        return getString();
    }

    public byte[] getOctets() {
        return string;
    }

    void encode(DEROutputStream out) throws IOException {
        out.writeEncoded(UNIVERSAL_STRING, this.getOctets());
    }

    boolean asn1Equals(DERObject o) {
        if (!(o instanceof DERUniversalString)) {
            return false;
        }

        return this.getString().equals(((DERUniversalString) o).getString());
    }

    public int hashCode() {
        return this.getString().hashCode();
    }
}
